libbpf: Verify that arena map exists when adding arena relocations

[ Upstream commit 42be23e8f2 ]

Fuzzer reported a memory access error in bpf_program__record_reloc()
that happens when:
- ".addr_space.1" section exists
- there is a relocation referencing this section
- there are no arena maps defined in BTF.

Sanity checks for maps existence are already present in
bpf_program__record_reloc(), hence this commit adds another one.

[1] https://github.com/libbpf/libbpf/actions/runs/16375110681/job/46272998064

Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250718222059.281526-1-eddyz87@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Eduard Zingerman 2025-07-18 15:20:59 -07:00 committed by Greg Kroah-Hartman
parent efaa18e467
commit 9ea8fb379f

View File

@ -4546,6 +4546,11 @@ static int bpf_program__record_reloc(struct bpf_program *prog,
/* arena data relocation */
if (shdr_idx == obj->efile.arena_data_shndx) {
if (obj->arena_map_idx < 0) {
pr_warn("prog '%s': bad arena data relocation at insn %u, no arena maps defined\n",
prog->name, insn_idx);
return -LIBBPF_ERRNO__RELOC;
}
reloc_desc->type = RELO_DATA;
reloc_desc->insn_idx = insn_idx;
reloc_desc->map_idx = obj->arena_map_idx;